1. Field of the Invention
The present invention relates to a device for controlling the flow of a fluid, more especially a biological fluid and in particular the urinary flow, as well as a prosthetic organ equipped with this device and a process for manufacturing such a device.
2. Description of the Prior Art
French Pat. No. 2 251 302 describes a sphincteral prosthesis, implantable in an endo-urethral or ano-rectal position more especially, which is provided with an external activation mechanism of the electro-magnetic type, and more precisely, the regulation device intended to replace a damaged or deficient sphincter is formed by a tube portion housed in the natural duct concerned and by an inflatable bag inserted inside this tube portion, so that the aperture of this latter is closed off in the completely inflated condition, whereas the opening of this aperture is obtained by deflation of the bag.
Closing and opening of this tube portion, namely the inflation and deflation of said bag, are obtained by means of a fluid which fills the bag and an expansion chamber defined by a metal bellows and communicating with the bag through a flexible duct which is preferably surrounded by a bell mouthed sealing collar near the point of its implantation in the tube portion wherein the movements of this fluid are controlled by an electro-magnetic device acting through the skin. However, handling of this electro-magnetic control device is not very easy and its design is relatively heavy.
An artificial sphincter device with hydraulic control is also known which is described in French Pat. No. 2 373 272 and which comprises: a collar for clamping the urethra by inflation under the action of the pressurized liquid, at least one deformable reservoir for inflating said collar, a valve system disposed between this inflation reservoir and the clamping collar, and means for deflating said collar, possibly comprising an auxiliary deformable deflation reservoir.
This device comprises a single valve applied against a seat formed in a dividing wall provided inside a case and separating a first chamber--defined in cooperation with a first bottom of the case, more especially the one which is on the same side as the clamping collar--from a second chamber communicating with said deformable reservoir for inflating said collar, and means for controlling the deflation of said collar.
According to one embodiment of this sphincteral device which corresponds to the absence of said auxiliary deformable deflation reservoir, said dividing wall provided with the valve seat and the walls of said case are deflatable, so that they themselves form said means for controlling the deflation of the clamping collar, the single valve being in this case formed by a resilient, so deformable, tongue fixed to this dividing wall by one of its ends, and, the deformable case and said deformable inflation reservoir may be mounted on a rigid support. Said case comprises two pipes connected to said first and second bottoms, more precisely the first pipe connects said first chamber to said clamping collar whereas the second pipe connects the second chamber to said deformable inflation reservoir.
The main drawback of this second French patent resides in the fact that said resilient tongue is fixed to said dividing wall and in the fact that the separation from the normal application against its seat, during inflation of the collar by deformation of said reservoir, requires the application of a relatively high pressure, which justifies the use of said rigid support.
Furthermore, U.S. Pat. No. 3,854,469 describes a device for controlling the flow of a fluid through an anatomical duct through which flows a physiological fluid, such as urine through the urethra. This device comprises a first inflation means formed by a first flexible chamber containing, in the rest state, a sufficient amount of fluid to stop the flow of fluid in said anatomical duct when it is applied against the external wall of this duct, a valve means provided with a relatively narrow fluid passage which is sensitive to the hydrostatic pressure difference existing between the ends of this passage as well as to the pressure obtained by manual deformation of said first chamber, or of a second inflation means formed by a second flexible chamber which is connected to the first chamber by said valve means and which is intended to receive the fluid initially contained in this first chamber under the action of a pressure applied by manual deformation of this latter, the flow rate of the fluid from said first chamber to said second chamber being relatively high whereas the flow rate in the reverse direction (namely from said second chamber to the first one), under the action of the hydrostatic pressure difference existing between the first and second chambers, is relatively low and is cancelled out when the pressures between the two chambers are balanced out with, when the corresponding flow is cancelled, the closure of said fluid passage (the flow time under the action of said hydrostatic pressure difference depends on the dimensions--length and diameter--of this passage: this time may be reduced by exerting the pressure obtained by manual deformation also of the second chamber). Furthermore, this American patent states that the first chamber is maintained applied against the external wall of the duct, the flow rate of which it is desired to control, by means of a ribbon, the second chamber is provided with a natural rubber plug so that, if required, fluid may be added by hypodermic injection, and the valve means comprises a resilient body, made more especially from silicon elastomer which is dilatable under the action of the manipulations of said chambers for establishing a relatively high flow rate between these chambers.
The main disadvantage of this American patent is that it is also sensitive to the hydrostatic pressure difference existing between said two deformable chambers, which is not always desirable in this type of application. In addition, subcutaneous implantation thereof, like that of said second French patent, is relatively complicated.
A urethral prosthesis also exists which is placed in position through the endo-canalar path, and which is interchangeable (see the article in Annales d'Urologie, 1982, 16, No. 5 pages 285-288). This urethro prosthesis is formed by a tube about 15 cm in length and with a variable diameter, made from silicon elastomer.
This tube has anti adherent surfaces obtained by molding, two drain orifices situated at one centimeter from its proximal end, and a double plurality of studs preventing axial movement thereof, without however preventing manual extraction thereof, which are formed on the mean outer part of the tube and which are directed upwardly and downwardly respectively.
The uncontested advantage of this urethral prosthesis is that it may be changed, on request, without surgery; however, use thereof is limited to radic urethritis and to multiple recurring stenosis in man only and does not concern incontinence.